Process for obtaining aluminium fluorid.



memes. No Drawing, I

ES A. DOREM' US, OF NEW YORK, N. Y., ASSIGNOR OE ONE-HAIFTTO JO SHERMAN HOYT, DARIEN, CONNECTICUT.

To all whom it may concern -Be it known that I, CHARLES A. DOREMUS,

- a citizen of the United States, and a resident of New York, county of-New York, and State of New York, have invented certain new and useful Improvements in Processes for Obtaining Aluminium F1uorid,of which the following is a specification.

-My invent1on relates to improvements in processes for obtam n alumlmum fiuorld,

. and the main object o my invention is to cordin provide .a rocess by which aluminium fluorid may e produced from felds ar or other refractory double silicates of 1i e nature. A further object of my invention is to provide a process in which valuable byproductsare obtained such as silica, and which may be advantageously used inconjunction with other processes for obtaining useful products from feldspar, etc.

In carrying out my improved process in its best form, I treat finely powdered orthoclass or the double silicate of otassium and aluminium (K O,A.l,O,,6SiO with aqueous hydrofluoric acid in the proportions of 20 parts by weight of the feldspar to 129 parts of the aqueous acid containin 20% of real acid at a temperature of a out 50 0., stirring the mixture thoroughly. The proportions will, of course, vary with different. feldspars and silicates, according to the percentages of metals present, and also acto the kind of fluorin acid used. The mixture becomes further heated by the chemical actions which take place, and there results in a-short time a complete decomposition of the feldspar. I then cool the mass somewhat and filter out theinsoluble potassium silicofiuorid, leaving aluminium fiuorid usually mixed with hydrofluosilicic acid in solution. The insoluble products .may be treated in any suitable way to obtain Specification of Letters Patent.

liquor resulting is either returned to the PROCESS FOR OBTAINING ALUMINIUM FLUORID.

Patented Aug. 21, 191?.

Application flied February 21, 1913. Serial No. 749,806.

tion and that added by the use of the aluminous ore is separated in an insoluble state and may be removed from the liquor by sedimentation or filtration. .The liquor then is practically a solution of aluminium fluorid. This substance is then obtained, if desired, in a solid state from the solution by either the evaporation of the water or by crystallization. In the latter case the amount of water of crystallization varies with the conditions under which the solution of aluminium fluorid is crystallized. Though these several forms of crystalline aluminium fluorid vary in solubility and in other properties, they all yield anhydrous aluminium fluorid when lieated.

When the aluminium fiuorid is obtained by either evaporation of the water from the solution, or by crystallization, the mother process or suitably treated to recover any valuable constituents.

The silica remaining on the filter, or secured by sedimentation, is in a finel divided condition and hydrated. Its purity is 8 dependent on the character of the ores used in the process. When heated it is rendered anhydrous. It is therefore suited, through its ready solubility in alkalis and through other properties to various useful purposes, 85

and in the anhydrous state is useful in other manufactures. The weight of precipitated silica produced relatively to the weight of aluminium fiuorid, assumed as anhydrous for comparison, varies according to the pro ortion of silicium present in the solution 0 aluminium fiuorid, the presence of hydrofiuosilicic acid therein, and the amount of silica present inthe aluminous material used to neutralize the aluminium fluorid solution. Thus kaolin introduces more silica than bauxite.

Although I have described my improvements. with respect to certain embodiments with great detail, nevertheless I do not desire to be limited to such details except as clearly specified in the appended claims, since many changes and mo ifications may well be made without departing from the spirit and scope of my invention in its broader aspects.

Having fully and clearly described my improvements, what I claim as new and desire to secure by Letters Patent, is:

l. The process of making aluminium 1 10 fluorid and silica from refractory potash and soda bearing feldspars, which consists in treating the feldspar with aqueous hydrofluoric acid to decompose the feldspar and form an insoluble fiuosilicate from the alkali of the feldspar and a soluble fluorid of alutreating the solution while hot with aluminous material until it the preci itated silica from the aluminium .is neutral, separating fluorid so ution and recovering the aluminium fluorid in a solid state.

2. The process of making aluminium fluorid, whlch consists in treating refractory i double silicates bearing aluminium with an the precipitate from the soluble aluminium excess of fluorin acid to decompose the double silicate and form an insoluble fluosilicate from the alkali of the double sill-- cate, and a soluble fluorid of aluminium from thealumina of the double silicate, separating the insoluble fiuosilicate, and then treating the solution with aluminous material and separating the precipitated Sill? clous material from the soluble aluminium fluorid to recover the aluminium fluorid.

3. The process of making. aluminium fluorid from refractory double silicates bear mg alum nium, which consists in treating the double silicate with an aqueous fluorin acid to decompose the double silicate and form an insoluble fiuosilicate from the alkali of the double silicate and a solution of fluorid of aluminium from the alumina. of. the double silicate, separating out the insoluble fiuosilicate, and then adding aluminous material to the solution of aluminium fluorld to precipitate silica, and separating fluorid to recover the latter.

4. The, process of making aluminium fluorid from refractory double silicates bearmg aluminium, which consists of treating the double silicate with a fluorin acid to decompose the double silicate'and form an insoluble fiuosilicate from the alkali of the feldspar and a soluble fluorid of aluminium from the alumina of the feldspar and then separating the insoluble fiuosilicate from the aluminium fluorid.

from the alumina of the felspar. and then separating the insolublefluosilicate from the aluminium fluorid.

6. Process of making aluminium fluorid and silica from refractory potash and soda 6 bearing feldspars which consists in treating the feldspar with an aqueous. hydrofiuoric acid, of about twenty per cent. strength, to decompose the feldspar and. form an insoluble fiuosilicate from the alkali 7 of the feldspar and a. soluble fluorid of aluminium from the alumina of the feldspar, then separating the solution containing the aluminium fluorid and an hydrofluoric acid from the insoluble fiuosilicate and then 7 treatingthe solution of aluminium fluorid with aluminous material to precipitate silicate from the solution and then recovering the aluminium fluorid in a solidstate.

7. The process of making aluminium z;

bearing aluminium, which consists in treating the double silicate with an aqueous fiuorin acid of about twenty per cent. strength to thereby directly produce alus minium fluorid and hydrofluosilicic acid and then separating the solution containing aluminium fluorid and any'hydrofluo-silicic acid from the alkali fiuosilicate, then adding aluminous material to precepitate s1l1- 9 cate, and separating the precipitate from the soluble aluminium fluorid to recoverthe latter.

In testimony whereof I have signed my name to this specification, in the presence 9 of two subscribing witnesses.

CHARLES A. DOREMUS. Witnesses:

GORHAM ORosBY, EDWIN Susan.-

I 0 fluorid from refractory double silicates 

